He helped plant a seed and then watched it grow for 35 years.

Nicholas Willems, founder and longtime pastor of Mustard Seed Church in Lawrence, died Wednesday at his home. He was 85.

“He’s really been the rock of this church and is the one that guided it and kept it on course,” said Pieter Willems, one of Willems’ three sons and current senior church pastor. “Really, he was the steady hand at the helm though it all.”

Nicholas Willems started the church in 1974 with his wife, Ineke. It began as a small student-led ministry at Kansas University, where Willems earned his doctorate in civil engineering in 1963 and went on to serve as a professor for 30 years.

The church, 700 Wakarusa Drive, blossomed over the years and has a current congregation of between 400 and 500 people.

Born in 1924 in The Netherlands, Willems and his wife immigrated in 1948 to South Africa, and then in 1960 to the United States, where they settled in Lawrence.

Willems served as senior pastor at Mustard Seed until 1997. After handing the church over to his son, the elder Willems continued in a pastoral role until last month.

His son said Willems was a father figure for many and was known for having an opinion.

“He was a straight-shooter; you always knew what he thought and what he felt,” Pieter Willems said. “He would always tell you what he thought and what would be the best thing for you.”

A memorial service for Willems will be at 6:30 p.m. July 25 at the church.